Even with the crushing domination of firearms over other weapons, some still use "archaic" weaponry. Swords, axes, spear and bows are cheap compare to the costly firearms. Other prefer simplicity, or simply keep melee weapons as a backup in case their good old pistol jams.

In the real world, a melee weapon like a sword do not equal even the most basic of firearms. However melee weapons are a big part of D&D world, thus balancing both is important. Allowing the player to still be strong even if he fight with a mace. Firearms require maintenance, need to be reloaded and are costly, thus it natural to make a gun stronger than a sword. Superior firepower do not help when your gun jams.

Since no Asian-based culture exist in the world of grey sky (instead some of it is spread across many nations) it is customary to ban weapon such as Katana or other asian weapon. Same go with Arabic cultures, since Grey Sky is American-European oriented. This is why the list of weapons in Grey Sky is mostly limited to European weapons.